Scientists at the MPI for Brain Research visualize new protein synthesis in zebrafish
The newly synthesized proteins can be labeled in intact organisms via metabolic incorporation of non-canonical amino acids.
Determining what neural circuits and proteins are involved in encoding memories is a central goal in neuroscience. Flora Hinz and Erin Schuman from the Max Planck Institute for Brain Research, together with their collaborators Daniela Dieterich (Leibniz Institute for Neurobiology) and David Tirrell (Caltech), have now demonstrated that protein synthesis, known to underlie long-term memory formation, can be visualized in the intact larval zebrafish. Non-canonical amino acids bearing small bio-orthogonal azide groups were introduced into proteins in vivo using the cells´ own translational machinery. Via a "click reaction", the newly synthesized azide bearing proteins were labeled with either a fluorescent or a biotin alkyne, which allows for the identification and visualization of newly synthesized proteins.
In the study published in ACS Chemical Neuroscience, they show that azidohomoalanine, the non-canonical amino acid, is metabolically incorporated into newly synthesized proteins, in a time- and concentration-dependent manner, but has no apparent toxic effect and does not influence simple behaviors. This enables fluorescent labeling of newly synthesized proteins in whole mount larval zebrafish. The applied technique represents a powerful tool to investigate new global protein synthesis under a variety of conditions to link behavior to specific changes in the proteome and pave the way for visualizing newly synthesized proteins during learning and memory.